Catalyzed and uncatalyzed aftertreatment devices, are well known and widely used in various internal combustion engine applications for the aftertreatment of engine exhaust gases. For example, aftertreatment devices are useful for handling and/or removing exhaust materials, such as carbon monoxide, nitric oxide, unburned hydrocarbons and soot, in the exhaust stream of an engine.
Although particulate filters are sometimes not catalyzed on the interior surfaces, many aftertreatment devices commonly employ a catalyzed washcoat applied to interior surfaces within fluid passageways of a cellular structure, which often resembles an interior of a honeycomb structure. Undesired exhaust material(s) react upon the catalyst material of the catalyzed washcoat, thus diminishing the undesired exhaust material(s).
However, face-plugging of the fluid passageways at the inlet face of these aftertreatment devices continues to be an issue under certain operating conditions. As one specific example, such problematic operating conditions can occur when a diesel engine operates during less aggressive duty cycles, such as but not limited to, extended idling operation. Frequent start and stop operation and other transient operating conditions can also be problematic. Furthermore, face-plugging has been known to occur at the inlet face of aftertreatment devices, such as those used in diesel engine aftertreatment applications during cold ambient operating temperatures, or during relatively low exhaust temperature ranges, such as 220° C. to 400° C. Such face-plugging or fouling at the inlet face has been defined as residue, such as exhaust materials and/or soot particles that accumulates on the outer surface of the cellular structure at the inlet face of an aftertreatment device, and effectively reduces the open frontal area of the aftertreatment device. Face-plugging is problematic, because it can result in a sharp rise in backpressure in aftertreatment or exhaust systems, which in turn may affect engine operation and decrease system efficiency. Preventing the formation of the soot/coke deposits during such problematic operating conditions would be of benefit. Thus, there is a need to provide an improved inlet face that can prevent and/or eliminate face-plugging or fouling at the inlet face aftertreatment devices.